Clenching a fastener is well known in the art when the fastener is a staple. The two prongs of the staple can be bent inward—the most standard method—or they can be bent outward to distribute the load to a greater area of the workpiece.
In general, placing a nail into a wood workpiece at a precise angle and position does not result in an exact position, as would be desired. Since wood products have a grain, the path the nail travels can be altered, and when that happens, the exit point of the tip of the nail often is changed from its original “planned” position. This indeterminate nail path is not repetitive, and it is a definite problem for manufacturing or construction applications in which the tip of the nail is to be curled, so that the two substrate layers of the workpiece become clenched together.
The manufacturers of wood pallets sometimes use a separate, stationary (non-portable) fixture that positions a type of target, or anvil, beneath the bottom wood frame during the initial assembly steps for making a pallet assembly, and then use a nail gun to shoot nails through the multiple-layer workpiece. The tip of the nail, after passing through the multiple layers of the workpiece, will then curl beneath the bottom surface of the workpiece to clench the multiple layers together. Such a process is expensive and slow, since it is unwieldy to provide such large target fixtures and to work with them for the large number of nail-driving positions that must be made in the workpieces.
One improvement in such nailing systems would be to attach a movable anvil to a portable nail driving tool, so that the anvil is always positioned that the correct location beneath the nail driving region, as determined by the human user of the portable nail driving tool. This allows the human user to “fire” as many, or as few, nails as he or she desires at a particular position on the workpiece (e.g., a pallet), and the user will easily be able to see the exact position where the nail is to be driven. By having a portable clenching anvil attached to the tool, the user is able to concentrate on a particular location for placing multiple nails while being assured that the anvil is securely gripping against the bottom of the pallet at that precise location where the nails are being driven.